兴趣社交网络中的供需匹配研究:以豆瓣网为例

近年来兴起的兴趣社交网络中因其内在的商业价值引起了人们的注意.兴趣社交网络中涌现出大量的商品供需信息,带来的问题之一就是商品供需信息传播匹配效率低下.为解决上述问题,本文依托社会网络分析方法,探讨在具备小世界特性的兴趣社交网络中商品供需匹配的特点,研究商品传播和匹配的规律和提高匹配效率的策略.本文选取豆瓣网关注关系为实证数据,提出在兴趣社交网络中友邻信息相关度与供需信息传播匹配效率正相关的假设,并采用计算机仿真方法来验证假设.论文获取豆瓣网的社交网络数据、包括网络用户藏书数据和图书的标签数据,针对随机选取的1000个用户和200本图书作为实验样本,分别设计两套友邻信息相关度度量算法和两套兴趣社交网络中商品供需信息传播匹配算法,采用进行仿真模拟实验进行了比较.实验结果证实了人们对于商品检索的直观判断,得出在兴趣社交网络中,商品供需信息传播匹配效率与友邻信息相关度正相关的结论.     

认知图式理论在翻译建构中的意义及其具体运用

图式是指已有的知识经验在大脑中形成的“框图”,即知识结构。翻译中通过联想、搜索译入语中有关图式,进行套用、模仿、迁移和重构,有助于发挥译入语的优势,实现双语符号的成功转换。按照认知心理学观点,运用图式进行传译可包括三个方面,即运用原型匹配、运用模板匹配、运用“自上而下”搜索。     

程式内的创新与模式外的建构——茅盾短篇小说视角模式研究

从视角模式的角度看,茅盾的短篇小说几乎全部属于第三人称视角模式,其中包含编辑型全知叙述、中立型全知叙述、有限全知叙述、第三人称人物内视角叙述等多种类型;个别篇章情形稍显复杂,出现了二度叙事。但茅盾绝不循规蹈矩,而是既关注程式内的创新,又重视模式外的建构,以充分挖掘各种视角模式的不同修辞功能。这种形式实验的成功,一方面显示了作家天才的艺术创造力,另一方面对当代文学创作亦不无借鉴意义。     

A simple two-step procedure using the Fellegi–Sunter model for frequency-based record linkage

The widely used Fellegi–Sunter model for probabilistic record linkage does not leverage information contained in field values and consequently leads to identical classification of match status regardless of whether records agree on rare or common values. Since agreement on rare values is less likely to occur by chance than agreement on common values, records agreeing on rare values are more likely to be matches. Existing frequency-based methods typically rely on knowledge of error probabilities associated with field values and frequencies of agreed field values among matches, often derived using prior studies or training data. When such information is unavailable, applications of these methods are challenging. In this paper, we propose a simple two-step procedure for frequency-based matching using the Fellegi–Sunter framework to overcome these challenges. Matching weights are adjusted based on frequency distributions of the agreed field values among matches and non-matches, estimated by the Fellegi–Sunter model without relying on prior studies or training data. Through a real-world application and simulation, our method is found to produce comparable or better performance than the unadjusted method. Furthermore, frequency-based matching provides greater improvement in matching accuracy when using poorly discriminating fields with diminished benefit as the discriminating power of matching fields increases.     

政策变迁中公益牺牲与社会义务之调适——以城镇小区配套幼儿园移交政策为例

公共政策变迁中由于涉及对私主体财产权的拘束而执行困难,并影响政策目标实现的情形,在实践中屡有发生。城镇小区配套幼儿园移交政策就集中反映了此类问题。由于城镇小区配套幼儿园原所有者财产权之取得具有长期的政策背景,而产权移交又涉及其权利减损,进而出现政策执行困难。究其原因,是基于公共利益需要而产生的特别牺牲,与财产权的社会义务之间存在冲突。前者的不可期待性与后者的可期待性之间界限模糊。调控与助推理念的适用有助于调适二者的关系,促使利益调控成为行政法的基本任务之一,进而建构以比例原则、依法行政原则和溯及力标准为主要内容的调适标准,使公共利益维护和私人利益保障之间尽可能平衡,进而推动公共政策目标的实现。     

多媒体课件视觉效果与文本切换频率对文本理解的影响

采用3(课件视觉效果)×3(文本的切换频率)两因素混合实验设计,考察多媒体课件的不同视觉效果及文本的切换频率对理解文本内容的影响。结果显示:不同视觉效果多媒体课件的主效应极其显著,视觉效果Ⅱ优于视觉效果Ⅰ和视觉效果Ⅲ;不同的切换频率主效应显著,文本字数500左右的幻灯片切换5次效果较好;对课件的理想程度评定结果表明,被试对视觉效果Ⅱ的评价得分较高。     

Efficiency or Competition? A Structural Econometric Analysis of Canada's AWS Auction and the Set‐Aside Provision

In 2008, Industry Canada auctioned 105 MHz of spectrum to a group of bidders that included incumbents and potential new entrants into the Canadian mobile phone market, raising $4.25 billion. In an effort to promote new entry, 40 MHz of spectrum was set‐aside for new entrants. In order to estimate the implicit cost of the set‐aside provision, we estimate the parameters of the bidders' profit function via a maximum match estimator based on the notion of pairwise stability in matches. We find that all telecommunications firms valued both geographic complementarities across auction licenses as well as absolute spectrum. Under a reasonable alternative scenario, our results indicate that the set‐aside led to a total profit loss of approximately 10%.     

农村地区食品安全监管配套制度的完善与落实

自2009年《食品安全法》颁布至今,我国农村地区的食品安全事件依旧频发,《食品安全法》在农村地区的实施效果远不如城市。造成这种状况的原因除长期以来存在的城乡二元结构和农村居民自身生活习惯等问题外,更主要的是《食品安全法》作为一部在全国范围内统一实施的法律,其明显缺乏专门针对农村食品经营主体的监管配套制度,从而使该法在广大农村地区实施的过程中监管能力明显不足。据此,提出构建食品安全监管在农村地区的配套制度,加强技术监管和信息化管理以及充分发挥社会共治等建议。     

摄影中的“新纪实”与“超现实”话语——以塞巴斯提奥·萨尔加多和杰瑞·尤斯曼为例

摄影是“自然之笔”与现实相对应。塞巴斯提奥·萨尔加多用镜头记录了真实的社会生活,其作品所表现的个体与群像在纪实品格外凸显出强烈的视觉美感和深刻性,形成了“新纪实摄影”风格;而杰瑞·尤斯曼的“超现实摄影”与前者相异,他用纯熟的后期暗房合成技术,通过底片叠加创造出现实中不存在的幻景,在具体与抽象之间拓展了作品的精神内涵和时空维度。文章以两位摄影大师为例,从三个维度来比较“新纪实摄影”与“超现实主义摄影”：“标记符”与“象似符”;“视觉寓言”;审美欲求。     

Quantifying the similarity of 2D images using edge pixels: an application to the forensic comparison of footwear impressions

We propose a novel method to quantify the similarity between an impression (Q) from an unknown source and a test impression (K) from a known source. Using the property of geometrical congruence in the impressions, the degree of correspondence is quantified using ideas from graph theory and maximum clique (MC). The algorithm uses the x and y coordinates of the edges in the images as the data. We focus on local areas in Q and the corresponding regions in K and extract features for comparison. Using pairs of images with known origin, we train a random forest to classify pairs into mates and non-mates. We collected impressions from 60 pairs of shoes of the same brand and model, worn over six months. Using a different set of very similar shoes, we evaluated the performance of the algorithm in terms of the accuracy with which it correctly classified images into source classes. Using classification error rates and ROC curves, we compare the proposed method to other algorithms in the literature and show that for these data, our method shows good classification performance relative to other methods. The algorithm can be implemented with the R package shoeprintr.